The ornamental design for an inverter, as shown and described.
FIG. 1 is a top, front and left side perspective of an inverter showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a back elevation view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a top, back and left side perspective view thereof.
The broken lines shown are for illustrative purposes only and form no part of the claim. Where broken lines abut a claimed surface it is understood that those broken lines represent an unclaimed boundary between claimed and unclaimed surfaces. None of the broken lines form any part of the claimed design.